First blow up the Horse Fly Ball and hang it on the desired location (half sun, half shade and away from children and animals). After that you need to apply the glue on the ball. Bring on a circle of glue around the ball, 10 centimeters away from the handle. Hold the handle while applying the glue to the ball. The glue gets hot and will slowly dripes down. With this brush, you can easily and advantageous dividing the glue.
And then.. catch those fly!